Pneumatic tool



PATNTED JAN. 5, 1904.

No. '748,568l

t R. L. AMBROSB.

PNEUMATIG TOOL.

APPLICATION FILED MAR. 22, 1901.

N0 MODEL.

UNITED STATES Patented January 5, 1904.

PATENT OFFICE.

ROBERT L. AMBROSE, OF TARRYTOWN, NEW YORK, ASSIGNOR TO RAND DRILL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK. i

PN EU MATIC TOOL.

SPECIFICATION forming part of Letters Patent No. 748,568, dated January 5, 1904. Application filed March 22| 1901. Serial No. 52,280. (No model.)

To all whom it may concern:

Be it known that I, ROBERT L. AMBROSE, a citizen of the United States of America, and a resident of Tarrytown,county of Westchester, and State of New York, have invented certain new and useful Improvements in Pneumatic Tools, of which the following is a specification, reference being had to the accompanying drawings, forming a part thereof.

My invention relates to improvements in pneumatic hand-tools, and particularly in pneumatic hammers and the like; and it consists in the novel means employed for preventing the cylinder or barrel from unscrewing from the handle and in the novel means whereby the shock and jar produced by the instrument in its operation is reduced.

lThe objects of my invention are to avoid unscrewing of the cylinders or barrels of pneumatic hand-tools from their handles and to reduce the shock and jar felt by the operator when the instrument is operating upon hard materials.

I will now proceed to describe a pneumatic hand-tool embodying my invention and will then point out the novel features in claims.

In the drawings which form a part of this specification, Figure l represents a central longitudinal section of an improved pneumatic hammer embodying my invention Fig. 2, a transverse section thereof through the locking-ring; Fig. 8, adetail section of the liner-bushing and locking-ring, showing the connection of the latter to the former by doWel-pins; and Fig. 4, a view illustrating a plurality of tools having different lengths of shank and which may be used in order to reduce the shock and jar felt by the operator.

In the embodiment of my invention illustrated in the drawings I have shown a pneumatic hand-tool l provided with a cylinder or barrel designated by the reference character a., a handle b, a piston c, having a projecting stem d, a chisel sleeve or bushing e, located in the mouth of the barrel, and a chisel f, the shank of which isloosely mounted within the bushing e, but which is otherwise entirely disconnected from the piston or otherparts of the apparatus.

' i The handle bis provided with a nipple g for connection with a hose through which air or other motive iiuid under pressure may be supplied. An air-chamber h is arranged within the handle, and a supply-duct vl is provided to convey the working fluid to the cylinder. A throttle-valve j is located in a port connecting the air-chamber h and the duct z' and is arranged to be operated by a thumblever lo. The handle is likewise provided with a check-valve Z, through which a lubricant may be inserted for the purpose of lubricating the Working parts.

The particular hand-tool illustrated in the drawings belongs to the valveless type, in which the supply and exhaust ports of the cylinder are opened and closed by the piston itself; but the arrangement oi' ports forms no portion of the present invention 'and the ports are not illustrated completely. The invention is applicable to any other pneumatic tool,whether of the valve or valveless type.

That portion of the barrel a. which constitutes the Working cylinder proper is provided with a liner-bushing m, in which the ports are cut and in which thepiston reciprocates.

In tools of this class it is customary to connect the barrel and the handle by screwthreads, the handle being provided with a screw-threaded socket adapted to receive the screw threaded upper end of the barrel. Such is the case -in the instrument shown in the drawings; In the past, however, much difficulty has been experiencedin preventing the barrel from unscrewing from the handle, the shock and jar due to the operation of the instrument making it very ditiicult to screw the barrel and handle together so tightly that the barrel shall not work loose and various locking devices which have been employed to prevent rotation of the barrel with respect to the handle have proved insufficient or unsatisfactory. In the drawings I illustrate an improved locking device for this purpose.

Between the end of the barrel a and the botto'mof the socket in the handle b, which receives the end of the barrel, there is a disk n, which, in fact, forms the cylinder-head and which may be grooved on its periphery. This disk is connected to the barrel a, as by dowel-V pins 0, as shown in Fig. 3, or in any other convenient manner. It is also provided with curved slots p, arranged to register with the supply-duct t and exhaust-port g and of such length that the disk may be moved through a considerable angle without disturbing such registry. These slots likewise register wlth the ports of the cylinder. A taper lockingkey fr is mounted in a transverse bore of the handle b, and the grooved periphery of disk n is in frictional contact with the surface of this locking-key. `Said key is provided with,

a nut for drawing it.up and locking it in place. The operation of this locking device is as follows: When the barrel and handle are to be connected, the locking-key r, if in place in the handle, is removed or pushed back. The barrel and handle are then screwed together as tightly as may be convenient, the disk n, of course being in place upon the end of the barrel. The locking-key r is then inserted, if not already in place, and is drawn home tightly by means of its nut. When so drawn home, it presses tightly against the disk fn, and the direction of the screw-threads of the barrel and the direction of the taper of the key fr are so arranged that such rotation of the barrel as would tend to unscrew the barrel from the handle would by reason of the frictional contact-key 1' and disk n also tend to draw up the key o". The barrel a cannot then accidentally rotate and unscrew itself from the handle, for in its rotation it would cause the key r to press yet more firmly against the disk fn. This locking device has the advantage over ratchet devices hitherto employed that it holds firmly in all positions of the barrel and not in certain angular positions only. By it therefore the handle and barrel may be clamped together so firmly that there can be no looseness and no leakage of the motive fluid. The locking device also has the further advantage that it contains no springs which by breaking can render the locking device inoperative.

The disk 'n is in function a part of the barrel at and is made separate therefrom only for convenience in manufacture.

In the use of pneumatic tools in stone-cutting and in metal-working much discomfort is caused to the operator by the fact that a tool which works satisfactorily on soft material will transmit excessive vibration and shock when used on harder materials. It is essential that every hand-tool shall be equally adapted for all kinds of Work and shall not cause excessive fatigue to the operator when used on any material. I have found that this adjustment and adaptation of the tool may be effected by varying the length of shank of the chisel or other tool which the pneumatic tool operates, using a tool with a relatively short shank for hard material and using tools with longer shanks for softer material. This is illustrated in Fig. 4, in which the three tools s, t, and u there shown have progressivelyshorter shanks. By tting each pneumatic hand-tool with a number of bits or tools of dierent lengths of shank for use on dierent materials the hand-tool may be adapted for any use and excessive shock and jar to the operator avoided.

It will be understood that any kind of tool which a pneumatic hand-tool may operate may be used in place of a chisel.

It is obvious that modifications of the particular construction and combination of parts as herein set forth may be resorted to within the spirit and scope of my invention.

Having thus completely described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In a .pneumatic hand-tool, the combination with a barrel and a handle, separably connected by screw-threads, of a taper key mounted in a transverse way in a portion rigid with one of said members, and in frictional contact with a portion rigid with the other of said members, and provided with means for locking it in position.

2. In a pneumatichand-tool, the combination with a barrel and a handle, separably connected by screw-threads, of a taper key mounted in a transverse way in a portion rigid with one of said members, and in frictional contact with a portion rigid with the other of said members, and provided with means for locking it in position, the taper of said key being in such direction of rotation of that member with which it is in frictional contact as is required to unscrew that member from the other. g

3. In a pneumatic tool, the combination with a `barrel and a handle, separably connected by screw-threads, of a locking means in frictional engagement therewith, said frictional engagement tending to increase upon a movement of the members to unscrew, and to decrease upon a movement of the members to screw up. Y

4. In a pneumatic hand-tool, the combination with a barrel and a handle, separably connected by screw-threads, of a disk secured to the barrel but interposed between the barrel and thel handle, and a taper key mounted in a transverse way in the handle, in frictional contact with said disk, and provided with means whereby it may be locked in position.

5. In a pneumatic hand-tool, the combination with a barrel and a handle, separably connected by screw-threads, of a disk secured to the barrel but interposed between the barrel and the handle, and having slots adapted to register with the ports of the handle and barrel, and a taper key mounted in a transverse way in the handle, and in frictional contact with said disk, and provided with means whereby it may be locked in position.

6. The combination with a pneumatic hand- IOO IIO

tool having a barrel or cylinder adapted to be adapted for working upon different matereceive free tools, and having also a. piston rials. adapted to drive such tools, of a plurality of tools therefor having Shanks of different 'ROBERT L' AMBROSE 5 lengths, whereby by substituting a tool hav- Witnesses:

ing one length of shank totI a tool having a D. HOWARD HAYWOOD, different length of shank, the hand-tool may HERMAN A. HENKE. 

